With the use of increasingly wider bandwidths and higher data rates, mobile communication services in recent years are realizing multimedia services such as music and video images. Furthermore, in order to realize much faster data services, the 3GPP (3rd Generation Partnership Project), which is a mobile communication technology standards organization, is studying a mobile communication technology called “LTE (Long Term Evolution)” that realizes a data rate of 100 Mbps or higher. On the other hand, to respond to such a high-speed radio access network and accelerated adoption of IP technology for the network, expansions of a mobile network configuration and node functions (SAE: System Architecture Evolution) are under review.
Examples of techniques for managing movement of radio communication terminal apparatuses (hereinafter referred to as “UE”) in a mobile communication system realized through LTE/SAE include a handover technique that manages movement of a UE carrying out data communication between cells and an idle mobility technique that manages movement of the UE in a waiting state (hereinafter referred to as “idle state”) within a mobile communication system.
In idle mobility, a network manages the position of the UE in a unit called “tracking area” and the UE updates the tracking area (hereinafter referred to as “TAU: Tracking Area Update”) to a radio communication mobility management apparatus (hereinafter referred to as “MME: Mobility Management Entity”) on the network side every time a boundary of tracking areas is crossed, that is, every time the UE moves to the tracking area of a different tracking area identifier (hereinafter referred to as “TAI: Tracking Area Identifier”). Through this TAU, the network can manage the latest UE movement situation in tracking area units and can send a paging message for a call connection to the UE.
As the TAU method, a multi-TA registration scheme is adopted whereby a plurality of peripheral TAIs are assigned to one UE (see FIG. 1 and FIG. 2). This multi-TA registration scheme eliminates the necessity for a UE located on a tracking area boundary to perform TAU frequently, and can thereby reduce the signaling load originating from TAU (i.e. the load originating from signaling).
On the other hand, the next-generation mobile communication system is studying adoption of femto cell base stations (small-cell radio communication base station apparatuses) that cover small zone areas of several tens of meters (i.e. femto cells) such as a home, office or restaurant in addition to large cells or macro cells currently in operation. A femto cell base station under review in the 3GPP is designed to allow, when, for example, installed at a home, only restricted group members to have access such as limiting access to only family members of the home. Such a cell may be referred to as an “access-limited cell (CSG cell: Closed Service Group cell).”
Furthermore, a UE which is granted access is preferentially connected to a femto cell base station. That is, as shown in FIG. 3, when the UE enters the area of the femto cell base station, even if the UE can receive radio waves of a macro cell, the UE is preferentially connected to a small-cell radio communication base station apparatus.    Patent Document 1: Japanese Patent Publication No. 2907678    Non-Patent Document 1: 3GPP TSG RAN WG3 Document, R3-070143 “Tracking Area Concept”